Minimum Radii


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I have a Blueline ATSF 4-8-4. According to BLI specs, this locomotive will operate on minimum 18" radius. I tried it on such small radius, and while it will run it does not do so efficiently.

I just received a new Genesis UP FEF 4-8-4. Athearn's specs indicate a minimum 22" radius for this locomotive; however, by looking at it locomotive I'd opine that this is too tight. Has anyone used this locomotive on a 22" radius?

I am in the planning phase of my future layout. I am trying to figure out dimensions for it. 22" radii would be a lot easier to fit in. But I don't want to design it with 22" radii if my locomotives will experience difficulty negotiating them. Would I be better off planning my layout using 24" radii?

BTW, I have E-Z Track with 28" radius. All of my locomotives work extremely well on it. If there were a way I could construct my future layout using 28" radius, I would.


Thanks,

Tom
 
If you have the opportunity to build future expansion or future usage that involves wider curves, always build wider curves into any layout. The time may come when you would like to run a cheaply purchased brass Pacific 4-6-2 and it would probably need something like 26-28" curves, depending on the manufacturer. So it would have been great to have foreseen what every modeler goes through, and that is first hankering after a large gee-whiz steamer and then getting it. Then realizing that the curves are a whole 1/2" too tight.

Seriously, I operated my BLI Niagara reliably on 22" EZ-Track on my first layout just three years back. I would bet that if you have honest-to-goodness 22" centres, you will be fine with both engines. A Texas type 2-10-4 would be able to get around them in most cases (certainly not brass!) but it would have to be at walking speed. I could grind my BLI Pennsy J1 around those same EZ-Track curves, but it was a real squeaker.

Want my final advice....go wider if you have the room. I promise you that you will never regret going for 24" curves except when you realize that they won't run a brass 4-8-4...if you ever get one.
 
I'll second Crandell's advice. I have a 4-8-4 that runs on my 22" E-Z track curves as long as I limit it to about 40 smph. I spent considerable time aligning and leveling the curves to get the engine to run reliably. Even though it runs well enough, it looks very unrealistic, with way too much overhang. The wider the curve you can get in, the better. 28" curves are ideal for almost any type of engine and they will look much better operating over a wider radius curve.
 
Crandell and Jim,

Thanks for affirming what I have been thinking. Bigger radii seem to be more functional.

HO model railroading has been a most educational process for me. A few months ago I would have never imagined the complexities of this wonderful hobby. Then I was under the naive impression that all I had to do was buy locomotives, some cars, put them on tracks, and enjoy model railroading. Now I am close to understanding that simplicity is not controlling in model railroading.

I am going to try to incorporate 24" radii and larger in my layout. In fact, I am going to try to dedicate a train room in my new home. I want to, at all costs, avoid constructing a layout only to have to dismantle it because my locomotives will not work on it. And to this end, I sincerely thank you guys for sharing your knowledge. Had I came to you guys for advice before I got into this hobby, I know I would have saved a lot of money spared myself even more frustration.

Trains are fascinating. I can easily see myself collecting them just for their aesthetic value. In fact, I plan on buying a display case for my living room just for model trains.


Happy railroading,

Tom
 
Tom, if you really want to have a scale layout, you almost have to become a scale civil engineer. :) All the things that apply to 1:1 scale trains apply to our models, including grades and curves. I spent a lot of years repeating layouts and making the same mistakes before I started doing a lot of reading and joining clubs, where guys with lot more experience than me gave me a hand. Forums like this would have been a real life saver back in 1968.
 
In the Canadian Army, officers in basic training are told some truths that stay with them for the rest of their lives. One great gem is, "Time spent on recce is seldom wasted." Translated, it means time spent gathering useful information before devising a plan (and commiting lives and valuable material resources to it :eek:) will pay huge and lasting dividends.

Similarly, in this hobby of ours, time spent working out niggling details pays handsomly. Details such as how much grade you will need to get to X elevation when you realize you now have to make a transitioning vertical curve into that grade, and out of it, to keep engines from stalling and uncoupling. That superelevating on a curve should be done minimally and in the correct place...not as the curve commences but just before it. If you do them simultaneously, you compound the chances of a derailment. Make one change in orientation, followed by the other. Long framed steamers like stable track, not twisting track.

And on it goes. Enjoy the process that comes from enjoyable discoveries of facts. Put it all together in a carefully detailed plan, and then have at it.

And you are welcome, Tom. We fellows in model railroading watch out for one another. :)

-Crandell
 
Most guys in our local clubs try to use the largest radius curves they can, but there always a limit imposed by what your layout space is. Most models will run on 22r or even 18r but can look a bit odd doing it. Most of my larger steam are Rivarossi models and will run on 18" radius curves, but I run them at the local club where they are more like 30" or larger. Cheers Mike
 
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